Perhaps he meets a new trainer. If he wakes up in a different region, there could be a trainer passing by who is intrigued by Ash's strange appearance or situation. This trainer could either be helpful or see Ash as some sort of oddity to be captured or studied.
He might meet Pikachu first. Since Pikachu is his closest and most loyal Pokemon friend, it would be likely that Pikachu would be by his side when he wakes up. Pikachu could be really confused at first but still show concern for Ash in his new state.
It could be a wild Pokemon. Maybe he wakes up in a forest and the first thing he sees is a curious Pidgey or a mischievous Meowth. This would set the tone for his new adventure as a Pokemon or in a Pokemon - like state, having to interact with the local Pokemon population right from the start.
He might meet an old Pokémon expert who gives him tips on hatching the egg.
In this kind of fanfiction, Ash might wake up with new Pokemon - like abilities. For example, he could communicate with Pokemon in a more direct and profound way, like understanding their every thought and emotion just by looking at them. He might also find himself physically changed, perhaps having some physical features of a Pokemon, which could lead to all sorts of interesting adventures and interactions with his friends and other Pokemon trainers.
He'll surely meet the Alola region's professors. Also, the local trial captains are very likely to cross paths with Ash. And of course, the regular Pokémon trainers in Alola.
He might meet new Pokémon trainers in Alola. Maybe some young kids who are just starting their own Pokémon journey.
He might meet a mysterious old wizard. The wizard could be the one who brought Ash to the room, either for a purpose or by accident. The wizard could then guide Ash on a journey, or perhaps be an antagonist who has some dark plan for Ash.
There might be a young and inexperienced trainer who is lost. Ash, being the more experienced one, decides to help the trainer find their way. This new character could look up to Ash and in the process, Ash learns more about himself as a role model. It would be an interesting dynamic as Ash is usually the one being guided by his friends.
Ash could be a Pokémon trainer with a different starting point in this fanfiction. Born in 1987, by 1997 he might have already made a name for himself in local Pokémon battles. He could have a team of Pokémon that he rescued from difficult situations, like a Charmander that was abandoned by its trainer. His story could revolve around giving these Pokémon a second chance and proving that Pokémon don't need to be 'perfect' to be strong.
Pikachu is a very likely candidate. It's Ash's most iconic Pokemon and has a deep bond with him. Whenever Ash is in trouble, Pikachu often steps up to protect him.
In a fanfiction about Ash born in 1987 and his situation in 1997, we could see an alternate story where Ash is not the typical rookie trainer. Since he's a bit older than in the original, he might be more knowledgeable about Pokémon lore. He could be on a quest to uncover some ancient Pokémon secrets in 1997. He might travel to different regions, not just for battles but also to study old Pokémon texts and artifacts, and along the way, form an unusual team of Pokémon that are attracted to his in - depth knowledge.
One popular aspect of Alola fanfiction with Ash could be his growth as a trainer. In the Alola region, Ash had unique experiences. Fanfiction might explore how he further developed his skills, formed new bonds with Pokemon, and interacted with the local culture. For example, his relationship with Pikachu might be delved into deeper, showing how they overcame new challenges together in the Alola setting.